Centrifugal compressor with diffuser

Abstract

A centrifugal compressor including a one-piece diffuser ring having a circumferentially extending vaneless diffuser space for receiving compressed gas exiting the compressor impeller, and for guiding the compressed gas to a plurality of outwardly extending and circumferentially arranged diffuser channels each of generally circular cross-section.

What is claimed is: 
     
       1. In a centrifugal compressor having a centrifugal impeller rotatably carried within a compressor housing having an annular chamber for receiving compressed fluid discharged radially outwardly from said impeller upon impeller rotation, a diffuser section comprising a unitary diffuser ring closely and circumferentially surrounding said impeller between said impeller and the discharge chamber, said ring including an annular vaneless diffuser space having a generally circular cross section openly communicating with said impeller for receiving fluid discharged radially outwardly from said impeller via a radially inwardly open throat, said throat having an axial width generally corresponding to the axial width of the radially outward extent of said impeller, and a plurality of linearly extending, generally circular cross section diffuser channels radiating generally outwardly from the vaneless diffuser space for guiding fluid from the vaneless space to the discharge chamber, said diffuser channels expanding radially outwardly over at least a portion of their lengths and being angularly oriented with respect to each other for intersection of their linear centerlines to form a tangency circle within said vaneless diffuser space and disposed radially outwardly from the radially outward extent of said impeller by a radial dimension greater than the radius of the diffuser channels at the innermost diameter of said channels. 
     
     
       2. A centrifugal compressor comprising a centrifugal impeller; a compressor housing receiving said impeller and including an annular discharge chamber for receiving compressed fluid discharged radially outwardly from said impeller upon impeller rotation; a shaft coupled to said impeller; process fluid bearing means for rotatably supporting said shaft; and a unitary diffuser ring closely and circumferentially surrounding said impeller between said impeller and the discharge chamber, said ring including an annular vaneless diffuser space having a generally circular cross section openly communicating with said impeller for receiving fluid discharged radially outwardly from said impeller via a radially inwardly open throat, said throat having an axial width generally corresponding to the axial width of the radially outward extent of said impeller, and a plurality of linearly extending, generally circular cross section diffuser channels radiating generally outwardly from the vaneless diffuser space for guiding fluid from the vaneless space to the discharge chamber, said diffuser channels expanding radially outwardly over at least a portion of their lengths and each being angularly oriented at an acute angle with respect to adjacent diffuser channels for intersection of their linear centerlines to form a tangency circle within said vaneless diffuser space and disposed radially outwardly from the radially outward extent of said impeller by a radial dimension greater than the radius of the diffuser channels at the innermost diameter of said channels. 
     
     
       3. In a centrifugal compressor having a centrifugal impeller rotatably carried within a compressor housing having an annular discharge chamber for receiving compressed fluid discharged radially outwardly from said impeller upon impeller rotation, a diffuser section comprising an annular unitary diffuser ring closely circumferentially surrounding said impeller between said impeller and the discharge chamber, said ring including an annular vaneless diffuser space in open communication with said impeller for receiving fluid discharged radially outwardly from the impeller, and a plurality of linearly extending, generally outwardly radiating diffuser channels of generally circular cross section for guiding fluid from the vaneless diffuser space to the discharge chamber, said diffuser channels being angularly oriented with respect to each other for intersection of their linear centerlines to form a tangency circle within said vaneless diffuser space and disposed radially outwardly from said impeller by a radial dimension greater than the radius of the diffuser channels. 
     
     
       4. A diffuser section as set forth in claim 3 wherein the vaneless diffuser space is formed to have a generally circular cross section, and a radially inwardly open throat for providing open communication between said impeller and the circular cross section portion of the vaneless diffuser space, and wherein the axial width of the throat generally corresponds with the axial width of the radially outer extent of the impeller. 
     
     
       5. A diffuser section as set forth in claim 4 wherein the vaneless diffuser space throat is defined by axially inner and outer walls, and wherein said inner and outer walls are contoured to match the operating characteristics of the associated impeller. 
     
     
       6. A centrifugal compressor comprising a centrifugal impeller rotatably carried within a compressor housing having an annular discharge chamber for receiving compressed fluid discharged radially outwardly from said impeller upon impeller rotation; and a unitary diffuser ring closely and circumferentially surrounding said impeller between said impeller and the discharge chamber, said ring including an annular vaneless diffuser space having a generally circular cross section openly communicating with said impeller for receiving fluid discharged radially outwardly from said impeller via a radially inwardly open throat, said throat having an axial width generally corresponding to the axial width of the radially outward extent of said impeller, and a plurality of linearly extending, generally circular cross section diffuser channels radiating generally outwardly from the vaneless diffuser space for guiding fluid from the vaneless space to the discharge chamber, said diffuser channels expanding radially outwardly over at least a portion of their lengths and being angularly oriented with respect to each other for intersection of their linear centerlines to form a tangency circle within said vaneless diffuser space and disposed radially outwardly from the radially outward extent of said impeller by a radial dimension greater than the radius of the diffuser channels at the innermost diameter of said channels. 
     
     
       7. A centrifugal compressor as set forth in claim 6 including a shaft coupled to said impeller, housing means receiving said shaft, and process fluid bearing means for rotatably supporting said shaft with respect to said housing means. 
     
     
       8. A centrifugal compressor as set forth in claim 6 wherein the vaneless diffuser space throat is defined by axially inner and outer walls, and wherein said inner and outer walls are contoured to match the operating characteristics of the associated impeller. 
     
     
       9. A centrifugal compressor including a compressor housing having an annular discharge chamber for receiving compressed fluid, comprising a centrifugal impeller rotatably carried within the compressor housing for discharging compressed fluid radially outwardly to the discharge chamber upon impeller rotation; and an annular diffuser ring of unitary construction closely circumferentially surrounding said impeller between said impeller and the discharge chamber, said ring including an annular vaneless diffuser space in open communication with said impeller for receiving fluid discharged radially outwardly from the impeller, and a plurality of linearly extending, generally outwardly radiating diffuser channels of generally circular cross section for guiding fluid from the vaneless diffuser space to the discharge chamber, said diffuser channels being angularly oriented with respect to each other for intersection of their linear centerlines to form a tangency circle within said vaneless diffuser space and disposed radially outwardly from said impeller by a radial dimension greater than the radius of the diffuser channels. 
     
     
       10. A centrifugal compressor as set forth in claim 9 wherein the diffuser channels are formed to have a generally radially outwardly expanding conical configuration, and wherein the tangency circle is disposed radially outwardly from said impeller by a radial dimension greater than the radius of the diffuser channels at the innermost diameter of said channels. 
     
     
       11. A centrifugal compressor as set forth in claim 9 wherein the diffuser channels are formed to have a generally cylindrical portion communicating with the vaneless diffuser space, said cylindrical portion blending into a radially outwardly expanding generally conical portion communicating with the discharge chamber. 
     
     
       12. A centrifugal compressor as set forth in claim 9 including means for rotatably driving said impeller. 
     
     
       13. A centrifugal compressor as set forth in claim 12 wherein said driving means includes a shaft coupled to said impeller, and including housing means receiving said shaft, and process fluid bearing means for rotatably supporting said shaft with respect to said housing means. 
     
     
       14. A centifugal compressor as set forth in claim 9 wherein the vaneless diffuser space is formed to have a generally circular cross section, and a radially inwardly open throat for providing open communication between said impeller and the circular cross section portion of the vaneless diffuser space. 
     
     
       15. A centrifugal compressor as set forth in claim 14 wherein said impeller includes a plurality of contoured impeller blades for drawing fluid axially inwardly upon impeller rotation and for discharging the fluid in a compressed state radially outwardly, said blades having at their radially outward extent an axial width corresponding generally to the axial width of the vaneless diffuser space throat. 
     
     
       16. A centrifugal compressor as set forth in claim 14 wherein the vaneless diffuser space throat is defined by axially inner and outer walls, and wherein said inner and outer walls are contoured to match the operating characteristics of the associated impeller. 
     
     
       17. A centrifugal compressor as set forth in claim 16 wherein said inner and outer walls are formed to extend generally radially with respect to the axial direction of impeller rotation. 
     
     
       18. A centrifugal compressor as set forth in claim 16 wherein said inner and outer walls are formed to extend angularly with respect to the radial direction.